Some hybrid vehicles may include a driveline disconnect clutch that may be opened and closed to mechanically isolate an engine from a transmission. The driveline disconnect clutch may also isolate the engine from an electric machine in the driveline. The driveline disconnect clutch may be closed to increase the output of the driveline. The driveline disconnect clutch may be opened to reduce driveline inertia and allow the engine to stop rotating so that fuel may be conserved. However, the driveline disconnect clutch may wear over time and there may be differences between driveline clutches of different vehicles. Consequently, an application force or pressure at which the driveline disconnect clutch begins to transfer torque may vary. Further, the torque transferred by the driveline disconnect clutch over a clutch stroke may also vary between vehicles. Therefore, it may be difficult to mitigate torque disturbances in the driveline that may be caused by closing the driveline disconnect clutch.
The inventors herein have recognized the above-mentioned disadvantages and have developed a method of operating a hybrid vehicle driveline, comprising: adjusting torque output of a driveline integrated starter/generator (DISG) in response to a difference between a desired driveline torque and an actual driveline torque during at least partially closing a driveline disconnect clutch.
By adjusting operation of a DISG in response to a difference between a desired driveline torque and actual driveline torque during closing of a driveline disconnect clutch, it may be possible to provide a desired driveline torque. For example, torque output of a DISG may be adjusted in response to a torque sensor output during driveline disconnect clutch closing so that driveline torque matches a desired driveline torque even during closing of a driveline disconnect clutch. Thus, the torque sensor provides feedback of driveline torque to compensate for driveline disconnect clutch application errors.
The present description may provide several advantages. Specifically, the approach may improve driveline torque delivery. Further, the approach may improve compensation for a degraded driveline disconnect clutch. Further still, the approach may allow many vehicles having different driveline disconnect clutches to operate in a similar manner.
The above advantages and other advantages, and features of the present description will be readily apparent from the following Detailed Description when taken alone or in connection with the accompanying drawings.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.